In the field of integrated circuit (IC) chip manufacturing, various active and passive devices may be manufactured on a common semiconductor substrate and subsequently interconnected through back-end-of-line technology to collectively provide a variety of functionalities for the IC chip. Active semiconductor devices may include, for example, transistors such as field-effect-transistors (FETs). A FET may be, among others, a complementary metal-oxide-semiconductor (CMOS) FET which may include a p-type FET (pFET) and an n-type FET (nFET). Passive devices may include, for example, resistors and electronic fuses, the latter of which may be commonly known as e-fuse. Generally, an integrated circuit chip may include devices that are redundant to other devices, mostly active, in order to provide fault protection in situations where one or more of the active devices fail during regular operation. In the event that an active device fails, a redundant “back-up” device, through electronically programming a designated e-fuse, sometimes automatically, may be used to re-configure the IC chip such that continuity of functionality of the IC chip may be properly maintained.
Most recently, advanced transistors made with a replacement metal gate (RMG) process were introduced because of their superior performance, in some aspect, with respect to the conventional poly gate transistors. During the manufacturing of replacement metal gate transistors, all of sacrificial gate electrode may be etched away and be replaced with metal gate as is known in the art. However, this particular process may be incompatible with the manufacturing process of certain passive devices that were conventionally manufactured with poly gate transistors. For example, the manufacturing process for electronic fuse, which utilizes silicided poly structures, may require modification in order to be properly integrated into the new replacement metal gate (RMG) process. Specifically, the silicide poly structure, which is necessary in the formation of an e-fuse, needs to be properly protected during the etching process of sacrificial gate electrode of transistors that may be neighboring the e-fuse. As a result, additional protective masks, and lithographic patterning and etching processes associated with the making of such masks, may be required, which results in increased complexity and overall cost of the device manufacturing.
Therefore, there exists in the art a need to develop new method or process and device structures that are compatible with such new method or process, to better integrate the process of manufacturing e-fuse into the process of manufacturing transistors with replacement metal gate.